Techniques for the separation and analysis of biomolecules and cells are of crucial importance in many technical fields, including but not limited to biopharmacy, biotechnology, food technology, analytical chemistry, medicinal chemistry, and water purification. For instance chromatographic methods based on bioaffinity have been used for more than 50 years. One important bioaffinity system is the immobilized Protein A by which immunoglobulins will interact biospecifically. This makes it possible to isolate monoclonal antibodies in a very efficient fashion.
The most frequently used separation technique today is a chromatographic technique where the separation media is packed in a cylinder and connected to a chromatographic system which makes it possible to isolate the molecules of interest. One of several disadvantages with this technique is the process time. Not only does the separation itself take considerable time, it is also time-consuming to set up the chromatographic system. The instruments and the equipment are expensive and require time to set up. Further, expert knowledge and experience is needed to be able to handle the system and to evaluate the results.
Alternatives exist and the use of magnetic particles is one of them.
U.S. Pat. No. 6,623,655 discloses a method for the preparation of a metal chelating compound.
Zhao at al. in Lab Chip, 2009, 9, 2981-2986 describe a technology to manufacture particles with a compartment intended for cells and a compartment with magnetic nanoparticles.
U.S. Pat. No. 4,438,179, describes a polymer particle having magnetic particles bound to its surface. The magnetic material is bonded with a layer of a bonding polymer comprising functional groups which functional groups are ionic or capable of forming a metal chelate or complex. Alternatively the magnetic material is bonded by a polyethylene glycol and/or a polypropylene glycol.
WO 2012/015891 discloses a particle which may be porous with smaller inorganic particles on its surface. The particle is presented as a toner particle for printers.
GB 1577930 discloses adsorptive particles and magnetic particles embedded in a porous polymer matrix. The porosity of the matrix is such as to allow only molecules up to a certain molecular weight to penetrate into the interstices of the matrix, so that the product selectively adsorbs dissolved substances out of solution. The compounded materials, especially in the form of pearls, are especially useful in the food industry e.g. to separate unwanted trace flavors from various food products or to recover useful materials such as vitamins from various products. Particular applications include removal of bitter isohumulones from concentrated yeast extracts; and recovery of riboflavin from whey. The particles containing the selectively adsorbed substance are easily separated from the medium due to their magnetic properties and thus overcome separation problems encountered with prior art adsorptive materials of this type. The adsorptive particles may be e.g., of carbon, Al2O3, silica gel, activated Mg silicate, clays, etc. The magnetic particles may be e.g., of magnetite, gamma-Fe2O3, ferrites, etc. The porous matrix may be e.g. PVC, polyacrylamide (optionally crosslinked with epichlorhydrin) phenolic resins, nylon-6, 6 crosslinked with HCHO, etc.
U.S. Pat. No. 8,518,265 concerns a functional powder comprising magnetic particles, and hydrophobic groups and hydrophilic groups provided on the surfaces of the magnetic particles; where the number (M) of the hydrophobic groups and the number (N) of the hydrophilic groups satisfy the condition of M/N is 0.2-0.8. An independent claim is included for water treatment method (for example treatment of wastewater such as industrial wastewater) involving dispersing the functional powder in water containing impurities so that the impurities are adsorbed on the surface of the powder, and removing the functional powder having adsorbed the impurities from the water by use of magnetic force.
Porous polymer particles comprising magnetic material are used today for purposes such as purification of various substances etc. Although such particles are successfully used in commercial applications, there remains room for improvement. In prior art particles, the magnetic material in the particles occupies a significant part of the space in the particles which could be used for purification or analysis.
Thus there is a need in the prior art to provide particles for purification purposes with increased loading capacity. There is also a need for a simple and robust method both for manufacture and when using the particles for various purposes.